2-aryl-4:6-dihydroxy-1:3:5-triazines and process for their manufacture



United States Patent 14 Claims (Cl. 260-248) It is known that2-arly-4:6-diamino-1:3:5-triazines can be hydrolyzed with alkali metalhydroxides to form 2- ary1-4 6-dihydroxy-1 3 S-triazines (Germanspecification No. 1,026,456 published Mar. 20, 1958 to Badische Anilin-& Soda-Fabrik Aktiengesellschaft, Ludwigshafen, Germany). On the otherhand, it is known from US. specification No. 1,734,029 patented Nov. 5,1929 to George Barsky et al. and from German specification No. 963,331patented May 9, 1957 to Deutsche Gold-und Silber-Scheideanstalt vormalsRoessler, Frankfurt am Main, Germany, that the triazine ring of2:4:6-triphenyl-1z3z5- triazine is split with aqueous sulphuric acidwith quantitative formation of phenyl-carboxylic acid. Consequently, itcould not have been foreseen that hydrolysis of 2-aryl-4-:6-diamino-1:3:5-triazines with the aid of sulphuric acid would yield2-aryl-4 6-dihydroxy-1 :3 :5 -triazines.

The present invention is based on the unexpected observation that thetriazine ring remains substantially intact when2-aryl-4z6-diamino-1:325-triazines and 2-aryl-4-amino-6-hydroxy-1z3z5-triazines are hydrolyzed with sulphuric acid of ahigher concentration. In this manner aryldihydroxytriazines are obtainedin a very pure state and in good yields. This acid hydrolysis providesvarious other further advantages over alkaline hydrolysis. Inter alia,it is possible to manufacture aryl-dihydroxy-triazines containingsubstituents in the aryl residue, for example nitro or benzoyl groups,which are attached in the course of alkaline hydrolysis. Furthermore, itis easier to convert aryl-diaminotriazines that are sparingly soluble inalkali metal alcoholates, such as2-(anthraquinonyl-2)-4:6-diamino-1:3:5-triazine, into the correspondingdihydroxy compounds by using concentrated sulphuric acid as solventsince it has better dissolving powers. By virtue of the higher solventpower of concentrated sulphuric acid even large batches requirerelatively small reaction vessels, and this is of considerableindustrial importance. Thus, for example, 1 part by weight of2-phenyl-4z6-diamino-1:3:5-triazene can be smoothly hydrolyzed with aslittle as 1.4 parts by volume of 90% sulphuric acid without anytechnical difiiculty. In conjunction with the process disclosed in therecently published French specification No. 1,268,091, granted June 19,1961, to Sueddeutsche Kalkstickstoif-Werke A.G., Germanyaccording towhich the starting materials used in the new process, i.e. thearyl-diaminotriazines, can be manufactured in a very economical mannereven without using an organic solvent-the process of this invention,which is likewise performed in the absence of organic solvents, is ofspecial value.

The aryl-diaminotriazines or aryl-amino-hydroxytriazines to be used asstarting materials preferably contain there is less risk of the triazinering being split but on the other hand the risk of the aryl residuebeing sulphonated is greater. It is surprising that under theseenergetic reaction conditions very many products, including 2-phenyl-4z6-diamino-123:5-triazine, can be hydrolyzed without appreciablesulphonation. In certain cases, however, sulphonation may be desirable.

The working up of the hydrolysis product is extremely simple andconsists in pouring it into ice water, filtering and washing the filterresidue until the washings run neutral. In many cases the resultingproduct is analytically pure; otherwise it can be purified by dissolvingin a dilute alkali and reprecipitating with acetic acid.

The following examples illustrate the invention. Unless otherwisestated, parts and percentages are by weight:

Example 1 A mixture of 50 parts of sulphuric acid and 14 parts of2-phenyl-4:6-diamino-1z3z5-triazine was stirred for 15 hours at to. C.The solution was cooled to about 70 C. and then poured into a mixture of400 parts of water and 100 parts of ice and stirred for about one hour.The precipitated 2-phenyl-4:6-'dihydr0xy-1:3 :5- triazine was filteredoff, washed with water to remove the sulphuric acid and dried. Theproduct melted at 289-290 C. (corrected) with decomposition and wassubstantially pure. Yield: 12.3 parts=86.9% or" the theoretical.

C H O N .-Oxygen: calculated 16.92, found 17.13%. Nitrogen: calculated22.21, found 22.33%.

Example 2 By hydrolyzing 40 parts of 2-pheny1-4:6-diamino 1:3:5-triazinewith 100 parts (=55 .6 parts by volume) of 90% sulphuric acid asdescribed in Example 1 and adding the solution at 110 C. with vigorousstirring to 350 parts of ice water (about 1:1) and working up,substantially pure 2-phenyl-4z6-dihydroxy-1:3:5-triazine melting at286287 C. (corrected) with decomposition was similarly obtained. Itcontained 22.33% of nitrogen. Yield: 90.2% of the theoretical.

Example 3 A mixture of 28.2 parts of 2-phenyl-4:6-diamino-1:3:5-triazine and 100 parts of 94% sulphuric acid was stirred for 25hours at 140 to 145 C., cooled to 110 C. and the solution poured into350 parts of ice water (about 1:1) and worked up. Yield: 24.8 parts(=87% of the theoretical) of 2-phenyl-4:6-dihydroxy-1:3z5-triazinemelting at 286287% C. (corrected) with decomposition.

Example 4 A mixture of 100 parts of 94% sulphuric acid and 28.2 parts of2-phenyl-4:6-diamino-1:3z5-triazine was stirred for 25 hours at to C. ina closed vessel. After cooling, the reaction mixture was poured intoabout 600 parts of water and stirred until it had cooled to roomtemperature. The precipitated product was then filtered and dissolved in600 parts of 4.7% sodium hydroxide solution. Addition of 47 parts ofglacial acetic acid to this solution caused the 2-phenyl 4:6dihydroxy-1:3:5-triazine to precipitate; it was filtered, washed untilneutral and dried. Yield: 24.1 parts=84.5% of the theoretical. Meltingpoint: 289-290 C. (corrected) with decomposition. According to analysis,the reaction product was very pure.

C H O N .0xygen: calculated 16.92, found 16.99%. Nitrogen: calculated22.21, found 22.17%.

Example 5 parts of 2-phenyl-4:6-diamino-lz3z5-triazine were stirred into500 parts of 90% sulphuric acid. The temperature rose to 90 C. and thesolution obtained Was stirred for 15 hours at 120 to 125 C., cooled to95 C., and then stirred'into a mixture of 650 parts of ice and 1100parts of water. The mixture was thoroughly stirred, and the precipitated2-phenyl-4z6-dihydroxy-1:3z5-triazine was filtered and washed withwater. It was then thoroughly stirred in a solution of 84 parts ofsodium acetate in 2000 parts of water, again filtered, washed with waterand dried. V

The product, obtained in a yield of 90% of the theoretical, melted at286-287 C. (corrected) with decomposition.

A mixture of 169 parts of phosphorus oxychloride, 84 parts of phosphoruspentachloride and 37.8 parts of 2- phenyl 4:6 dihydroxy-1z3z5-triazine(prepared as described in the first paragraph of thisexample) wasstirred for 3 hours under reflux. The resulting solution whenfractionated gave a yield of 86.7% of the theoretical of substantiallypure 2-phenyl-4z6-dichlor0 1:3:5 triazine melting at 122-123 C.(corrected) and boiling at 162- 164 C. under 10 mm. Hg pressure.

When extremely pure 2-phenyl-4z6-dihydroxy-1 :3 5- triazine was used,the dichlorotriazine was obtained in a yield of 88.4% of thetheoretical.

Example 6 A mixture of 30 parts of2-'(4'-nitrophenyl)-4:6-diamino-1:3:5-triazine (melting point,corrected: 334 C.) and 300 parts of 80% sulphuric acid was stirred for20 hours at 118122 C. The mixture was allowed to cool slightly and thenstirred into 1000 parts of ice water. The precipitated 2-(4nitrophenyl)-4:6-dihydroxy-1:3:5-tri azinewas rapidly filtered andpurified via its sodium salt. For this purpose the moist product wasstirred in 500 parts of water, and the fine suspension made alkalinewith about 50 parts by volume of 30% sodium hydroxide solu tion. Theresulting sodium salt was rapidly filtered, dispersed in 500 parts ofwater and acidified with about 50 parts by volume of glacial acetic acidwhile being stirred. The batch was suction-filtered and the filterresidue washed with water and dried. The yield was 22.1 parts ofsubstantially'pure 2-(4'-nitrophenyl)-4:6-dihydroxy-1z3z5-triazinemelting at 318 C. (corrected) with decomposition. This compound couldnot be prepared as disclosed in German specification No. 1,026,456,published Mar. 20, 1958, to Badische Anilin- & Soda-FabrikAktiengesellschaft, Ludwigshafen, Germany.

. By reaction with phosphorus pentachloride this compound was convertedinto 2 (4' nitrophenyl) 4:6-dichloro-1z3z5-triazine which melted at 189C. (corrected).

. 7 Example 7 A mixture of 34 parts of2-(2'-nitrophenyl)-4:6-diamino-1:3:5-triazine (melting at 236 C.,corrected) and 120 parts of 80% sulphuric acid was stirred for 15 hoursat 105 to 110 C. The reaction mixture was allowed to cool andvigorouslystirred into 400 parts of ice water and then Worked up in the cold.Yield: 18.1 parts of 2-(2-nitrophenyl) 4:6 dihydroxy-lz3z5-triazinemelting at 267-268 C. (corrected) with decomposition.

On reaction withphosphorus pentachloride the above product gave a goodyield of 2-(2-nitrophenyl)4:6-dichloro-1z3z5-triazine melting at 119-120C. (corrected).

Example 8 4 lised on cooling and 2-(4-benzoylphenyl)-4:6-dihydrox1:3:5-triazine was obtained in a yield of 81% or the theoretical. Theproduct melted at 294295 C. (corrected) with decomposition and wasconverted into 2-(4'- benZoylphenyl)-4:6-d-ichloro 1:3:5 triazinemelting at 153 C. (corrected).

The above compound could not be manufactured by v the process describedin German Specification No. 1,026,456 published Mar. 20, 1958 toBadische Anilinand Soda-Fabrik, Aktiengesellschaft, .Ludwigshafen,Germany. 7

Example 9 A mixture of 10 parts of 2-(anthraquinonyl-2)-4:6--

diamino-1z3z5-triazine (melting above 360 C.) and 150 parts of 90%sulphuric acidwas stirred for 16 hours at 130 to 135 C., allowed to coolto 60 C. and then vigorously stirred into 500 parts of ice water. Theprecipitated 2 (anthraquinonyl-Z')-4:6-dihydroxy-l:3z5-triazine wasfiltered cold, washed with water and dried. Yield: 91%

v of the theoretical.

' rected) .hours at 110-115" C., then vigorously stirred into 250 a Theabove product could not be manufactured by the process disclosed inGerman specification No. 1,026,456, published Mar. 20, 1958 to BadischeAnilinand Soda- Fabrik Aktiengesellschaft, Ludwigshafen, Germany.

Example 10 OH N- A mixture of 5 parts of 2(4'-benzenesulphenyl)-4:6-diamino-1z3z5-triazine (melting at 300 C., corrected) and 50 parts ofsulphuric acid was stirred for 15 parts of ice water and .worked up inthe cold. Yield: 96%. of the theoretical of 2-(4'-benzenesulphophenyl)-4:6-dihydroxy-1:3:5-triazine which as obtained was=very pure and couldbe converted into an analytically pure form (melting at 330 C.,corrected with decomposition) by recrystallisation from aqueousdimethylformamide.

The 2 (4'-benzenesulphophenyl)-4:6-dichloro-1z3z5- triazine obtainedfrom the above product melted at 232 C. (corrected). V

Example v11 A mixture of 15 parts of 2-(3-trifluoromethylphenyl)-4:6-diamino-1:3:5-triazine (melting at 211 C., corrected) and 66 partsof 75% sulphuric acid was stirred for 12 hours at -110" C. The batch waspoured into 300 parts of ice water (1:1), stirred for 1 hour and theresulting 2 (3' trifluoromethylphenyl)-4:6-dihydroxy- 1:3:5-triazinefiltered 011; after having been washed with water'and dried it melted at305 C. (corrected) with decomposition. Yield: 81% of the theoretical.

The 2 (3'-trifluoromethylphenyl)-4:,6-dichloro-1:3:5- triazineobtained'from the above product melted at 98 C. (corrected).

Example 12 A mixture of parts of 2-(4'-methoxyphenyl)-4:6-diamino-lz3z5-triazine (melting at 235 C., corrected) and 40 parts of80% sulphuric acid was stirred for 16 hours at IOU-105 C. After cooling,the reaction mixture was vigorously stirred into 150 parts of ice waterand worked up in the cold. Yield: 90.2% of the theoretical of2-(4-methoxyphenyl) -4:6-dihydroxy-1 3 S-triazine, melting at 306308 C.(corrected) with decomposition. An analysis showed that this product wasvery pure.

C H O N .Oxygen: calculated 21.9, found 22.1%. Nitrogen: calculated19.17, found 19.33%.

The 2-(4'-met.hoxyphenyl) -4:6-dichloro-1 :3 S-triazine prepared fromthe above product melted at 138 C. (corrected).

Example 13 A mixture of 7.5 parts of 2-(diphenyl-4)-4:6-diamino-1:3:5-triazine melting at 277 C. (corrected) and 50 parts of 80%sulphuric acid was stirred for hours at 110-115 C. and then thoroughlystirred in 300 partsof ice water. The precipitated2-(diphenyl-4)-4:6-dihydroxy- 1:3:5-tn'azine was filtered, Washed untilthe washings ran neutral and purified via the sodium salt. For thispurpose the moist filter cake was heated to the boil in about 500 partsof water and dissolved by cautiously adding sodium carbonate solutionwith vigorous stirring. A small amount of insoluble material wasfiltered oil and the alkaline filtrate allowed to cool. The resultingcrystalline sodium salt was rapidly suctioned off, stirred With waterand acidified with hydrochloric acid. The batch when filtered, washedwith Water and dried, gave 2-(diphenyl-4')-4:6-dihydroxy-1:3:5-triazine,melting at 326- 330 C. (corrected) with decomposition, in a yield of 72%of the theoretical.

2 (diphenyl-4')-4:6-dichloro-123:5-triazine obtained from this productmelted at 161 C. (corrected).

Example 14 A mixture of 15 parts of 2-(2':5-dichlorophenyl)-4:6-diamino-1z325-triazine (melting at 269 C., corrected) and 75 parts of90% sulphuric acid was stirred for 15 hours at 120-125 C., allowed tocool, and the hydrolysis mixture then vigorously stirred into 300 partsof ice water (1:1), thoroughly stirred for a prolonged period, and theresulting 2-(2':5-dichlorophenyl)-4:6-dihydroxy- 1:3:5-triazine workedup; it melted at 268 C. (corrected) with decomposition. Yield: 75% ofthe theoretical.

The 2-(2':5-dichlorophenyl) -4:6-dichloro 1:3:5 triazine obtained fromthe above product melted at 135 C. (corrected).

Example 15 Hydrolysis of 10 parts of2-(4-methylphenyl)-4:6-diamino-1:3:5-triazine (melting at 242 C.,corrected) with 50 parts of 90% sulphuric acid for 15 hours at 120- 125C. gave 2-(4-methylphenyl)-4:6-dihydroxy-1:325- triazine in a yield of97% of the theoretical.

C H O N .Oxygen: calculated 15.75, found 15.92%. Nitrogen: calculated20.68, found 20.66%.

2-(4-methylphenyl)-4:6-dichloro 1:3:5 triazine obtained therefrom meltedat 150 C. (corrected).

Example 16 Hydrolysis of 14 parts of 2-.phenyl-4-amino-6-hydroxy-1:3:5-triazine (melting at 343 C., corrected with decomposition) in 50parts of 90% sulphuric acid for 15 hours at 120 to 125 C. yielded2-phenyl-4z6-dihydroxy-1:3z5-

triazine melting at 289-290 C. (corrected) with decomposition.

The starting material, 2-phenyl-4-amino-6-hydroxy- 1:3:5-triazine, couldbe prepared by the process of German specification No. 543,112 patentedJan. 14, 1932 to I. G. Farbenindustrie A.G., Frankfurt am Main, Germany,by heating benzoic acid (or its chloride or anhydride) withdicyandiamide.

The 2-aryl 4:6 diamino-1z3z5-triazines used in Examples 1 to 15 wereobtained by known methods from the corresponding arylcyanides, forexample in the following manner:

A mixture of 0.184 mol potassium hydroxide, 1 mol benzonitrile, 1.1 to1.2 mols dicyandiamide and 2.71 mols glycol monomethyl ether wasgradually heated to C. with stirring until the heat of reaction causedcondensation, during which efiicient cooling must be provided. When thereaction had subsided, the whole was heated for 4 hours at the boil andthen allowed to cool. The 2- ary1-4:6-diamino-1:3 :S-triazines generallycrystallised out; if not they could be precipitated with water. Theywere easy to purify by recrystallisation from aqueousdimethylformarnide.

In the case of sparingly soluble arylcyanides, such as 2-cyano-anthraquinone, the proportion of glycol monomethyl other used inthe process should be increased but only so much that condensation couldstill be effected.

What is claimed is:

1. A process for the manufacture of a 2-aryl-4z6-dihydroxy-l13:5-triazine which comprises hydrolyzing a manufacture selected fromthe group consisting of a 2- aryl-416-diamin0-123Z5-triazine and a2-aryl-4-amino-6- hydroxy-1:3:5-triazine with sulfuric acid of 70-96%strength.

2. A process as claimed in claim 1, wherein the hydrolysis takes placeWithin the temperature range .from 90 to C.

3. A process as claimed in claim 1, wherein for each part of a2-aryl-4z6-diamino-1 :3 :S-triazine at least 2 parts by weight ofsulphuric acid are used.

4. A process as claimed in claim 1, wherein a 2-phenyl-4:6-diamino-123z5-triazine is used as starting material.

5. The compound of the formula C II I O OH 6. The compound of theformula c 11 N-G 7. The compound of the formula 8. The compound of theformula 9. The compound of .the formnla 8 13. The compound of theformula References Cited UNITED STATES PATENTS OTHER REFERENCES Noller:Chemistiry of Organic Componndsfsecond.

edition, W. B. Saunders C0., Philadelphia (1957), page 481. v V i Gilman(ED.): Organic Synthesis, collective v01. 1,

Wiley and Sons, New York (1941), pp. 455-6.

Koopman: Rev. Trav. Chem, vol. 80, pp. 158-72 (1961), also Chem.Abstracts, vol. 55, col. l8755e.

WALTER A. MODANCE, Primary Examiner.

J. M. FORD, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,340,261 September 5, 1967 Eduard Moergeli It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 7, lines 33 to 37, the formula should appear as shown belowinstead of as in the patent:

Signed and sealed this 21st day of January 1969.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

1. A PROCESS FOR THE MANUFACTURE OF A2-ARYL-4:6-DIHYDROXY-1:3:5-TRIAZINE WHICH COMPRISES HYDROLYZING AMANUFACTURE SELECTED FROM THE GROUP CONSISTING OF A2ARYL-4:6-DIAMINO-1:3:5-TRIAZINE AND A2-ARYL-4-AMINO-6HYDROXY-1:3:5-TRIAZINE WITH SULFURIC ACID OF 70-96%STRENGTH.
 10. THE COMPOUND OF THE FORMULA
 12. THE COMPOUND OF THEFORMULA